Abstract: The hot carrier induced degradation of PDSOI NMOS devices fabricated on wafers modified by silicon ions implantation was elaborately studied in this paper in comparison with conventional devices. Theoretical analysis and TCAD simulation results show that the electron traps in the buried oxide layer induced by silicon ions implantation can capture the injected electrons and affect the intensity of impact ionization and hot carriers injection by altering the electric field. Meantime, the effect varies in different stress conditions. When hot carrier stress is applied to the modified device, there is a more significant interaction between the front and back gates of the modified device. The effect of total dose irradiation on the hot carrier degradation was also explored. The radiation enhanced hot carrier degradation also occurs in the modified devices and hightemperature annealing can only partially eliminate this effect.